A DOOM III trailer is apparently part of Microsoft's Xbox presentation at E3
this year, and the clip has been posted as subscriber-only content on IGN.
It's not clear whether that's the original clip, but a ShakyCam(tm) version (the
E3 special: shot off a monitor with a video camera) has been posted on Tiscali
Games as a 2.5 MB Windows Media Player file. Though this does not serve as
confirmation for the rumors that the Xbox will be the exclusive console system
for the game (story), it certainly could be seen as lending
support to that possibility. There are also a couple of DOOM III screenshots on The
Adrenaline Vault.

When did Doom come out and when did Half-Life come out?Doom3 is a retelling of original Doom's story.Do the math...

As for a storyline, there isn't one. You're a space marine on Phobos, some kind of experiment with some gate goes wrong, you have to clean shit up, with extreme prejudice. Funny enough, that sounds suspiciously like Half Life's "plot" to me as well.